Android Signature Pad Android Signature Pad is an Android library for drawing smooth signatures. It uses variable width Bézier curve interpolation based on Smoother Signatures post by Square.

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https://github.com/gcacace/android-signaturepad
https://github.com/szimek/signature_pad
Android Signature Pad
Android Signature Pad is an Android library for drawing smooth signatures. It uses variable width Bézier curve interpolation based on Smoother Signatures post by Square.

issue touch android smooth curve smoother signatures programming

 https://pub.dev/packages/hand_signature
hand_signature | Flutter Package
Published 8 months ago • verified publisher iconbasecontrol.dev

 https://www.b4x.com/android/forum/threads/signpad-v0-20-signature-capture-incl-java-source.50072/
SignPad V0.20 - Signature Capture - incl Java source | B4X Programming Forum
https://stackoverflow.com/questions/16455896/android-digital-signature-using-bezier
java - Android: digital signature using Bezier - Stack Overflow
https://stackoverflow.com/questions/8287949/android-how-to-draw-a-smooth-line-following-your-finger
java - Android How to draw a smooth line following your finger - Stack Overflow
https://stackoverflow.com/questions/8287949/android-how-to-draw-a-smooth-line-following-your-finger
java - Android How to draw a smooth line following your finger - Stack Overflow
javascript - Canvas SignaturePad doesn't clear on Mobile Phonegap App (Android) - Stack Overflow

Surface Pro 7
                issue affects every Surface Pro 7, Surface Pro X, and Surface Laptop 3.
                https://youtu.be/7jf2xTM4PMg?t=318
Please upvote the MS support threads and leave comments.
                https://answers.microsoft.com/en-us/surface/forum/all/surface-pro-7-pen-pressure-issues-with-palm/105fcbdb-0f05-4fde-a2df-804dfeafcb6e
                https://answers.microsoft.com/en-us/surface/forum/surfprox-surfdrivers/pen-pressure-staircasing-issue-when-touching-the/8c28cff4-0fb9-4ac3-8781-c22fa2ace98e
                https://www.reddit.com/r/Surface/comments/ehd79v/surface_pro_7_pen_pressure_issues_with_palm/fcio6ic/
Hopefully this issue won't take more than a year to fix, like that pen offset issue.
                https://www.reddit.com/r/Surface/comments/7of68m/surface_pro_intermittent_pen_inaccuracy_when_hand/
                https://answers.microsoft.com/en-us/surface/forum/all/surface-pro-7-pen-pressure-issues-with-palm/105fcbdb-0f05-4fde-a2df-804dfeafcb6e?auth=1
And Tablet Pro shows the issue alongside other bugs in a Video too:
                https://www.youtube.com/watch?v=7jf2xTM4PMg

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 https://developer.squareup.com/blog/smoother-signatures/
Written by Rob Dickerson.
Smoother Signatures Capturing even more beautiful signatures on Android.
Responsiveness Variable Stroke Width

Smoother Signatures | Square Corner Blog
https://medium.com/@robdickerson
Putting it all together, we have cubic spline interpolation making our signature smooth, velocity-based stroke width variance giving our signature character, and bitmap caching making our drawing responsive. The result is a delightful experience and a beautiful signature.

runtime drawing fourier transform epicycles 

https://9gag.com/gag/a1QeN3Y
Using epicycles and Fourier series, you can get an amazing automatic drawing generator
Drawing anything with Fourier Series using Blender and Python | by avantcontra | Medium

Coding Challenge #130.1: Drawing with Fourier Transform and Epicycles The Coding Train
Fourier Transform drawing 2.0  epicycles comments runtime drawing fourier transform epicycle 
https://wiki.tcl-lang.org/page/Drawing+with+epicycles+and+the+Fourier+transform
https://www.myfourierepicycles.com/
https://stackoverflow.com/questions/57117182/drawing-rendering-3d-objects-with-epicycles-and-fourier-transformations-animati
https://dsp.stackexchange.com/questions/59068/how-to-get-fourier-coefficients-to-draw-any-shape-using-dft
https://www.dynamicmath.xyz/fourier-epicycles/
Discrete Fourier Transform: Draw your system of epicycles – GeoGebra
Drawing with Fourier Transform and Epicycles / The Coding Train

https://cloud.tencent.com/developer/article/2215395?areaId=106001
android 电子签名 手写签名 功能实现-腾讯云开发者社区-腾讯云

package com.example.hand.views;

import java.util.ArrayList;
import java.util.List;

import android.content.Context;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.view.MotionEvent;
import android.view.View;

import com.example.hand.R;
import com.example.hand.utils.Bezier;
import com.example.hand.utils.ControlTimedPoints;
import com.example.hand.utils.TimedPoint;

public class SignatureView extends View {
    // View state
    private List<TimedPoint> mPoints;
    private boolean mIsEmpty;
    private float mLastTouchX;
    private float mLastTouchY;
    private float mLastVelocity;
    private float mLastWidth;
    private RectF mDirtyRect;

    // Configurable parameters
    private int mMinWidth;
    private int mMaxWidth;
    private float mVelocityFilterWeight;
    private OnSignedListener mOnSignedListener;

    private Paint mPaint = new Paint();
    private Path mPath = new Path();
    private Bitmap mSignatureBitmap = null;
    private Canvas mSignatureBitmapCanvas = null;

    public SignatureView(Context context, AttributeSet attrs) {
        super(context, attrs);

        TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.SignatureView, 0, 0);

        // Configurable parameters
        try {
            mMinWidth = a.getDimensionPixelSize(R.styleable.SignatureView_minWidth, convertDpToPx(3));
            mMaxWidth = a.getDimensionPixelSize(R.styleable.SignatureView_maxWidth, convertDpToPx(7));
            mVelocityFilterWeight = a.getFloat(R.styleable.SignatureView_velocityFilterWeight, 0.9f);
            mPaint.setColor(a.getColor(R.styleable.SignatureView_penColor, Color.BLACK));
        } finally {
            a.recycle();
        }

        // Fixed parameters
        mPaint.setAntiAlias(true);
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeCap(Paint.Cap.ROUND);
        mPaint.setStrokeJoin(Paint.Join.ROUND);

        // Dirty rectangle to update only the changed portion of the view
        mDirtyRect = new RectF();

        clear();
    }

sketch pen brush touch algorithm pressure tilt sensitive android axis_pressure java getpressure
https://developer.android.com/reference/android/view/MotionEvent
http://android-er.blogspot.com/2014/05/get-touch-pressure.html
Android-er: Get touch pressure

https://developer.android.com/reference/android/view/MotionEvent
https://developer.android.com/reference/android/view/MotionEvent#getHistoricalPressure(int)
https://developer.android.com/reference/android/view/MotionEvent#getPressure(int)

https://helpx.adobe.com/in/fresco/using/pressure-curve.html
Adjust pressure curve on stylus   pixel brushes, live brushes, or vector brushes to create your designs.

https://askubuntu.com/questions/48771/how-to-set-pressure-sensitivity-in-gimp-to-control-line-thickness
11.04 - How to set pressure sensitivity in GIMP to control line thickness? - Ask Ubuntu

https://askubuntu.com/questions/48771/how-to-set-pressure-sensitivity-in-gimp-to-control-line-thickness